Spark plug adjusting device



June 15, 1943- H. RABEzzANA r-:T AL 2,321,854

SPARK PLUG ADJUSTING DEVICE Filed Oct. 20, 1941 @la S Stwenfors Patented June 15, 1943 SPARK PLUG ADJUSTING DEVICE Hector Rabezzana and Alexander J. Battey, Flint, Mich., assignorsto General Motors Corporation, Detroit, Mich., a corporation of Delaware Application October 20, 1941, Serial No. 415,706

' 5 Claims.

Our invention consists in a device or tool designed to bend the grounded or shell electrodes of a spark plug to bring them into proper relationship with the central insulated electrode of the plug; to thereby reduce the length of the spark gap as the electrodes, particularly the extremities of the grounded electrodes, become eroded and worn away when the plug is in use. In order that a spark plug shall operate satisfactorily, the distancebetween the extremities of the grounded electrodes and the central elec,- trode, that is, the length of the spark gap, should be kept constant and as near uniform as possible; to which end the plug will be removed from the engine from time to time, or whenever it is thought that the spark gap is becoming too long because of erosion of .the electrodes, and the grounded electrodes bent toward the central electrode by the tool or device wherein our in vention consists; to vthereby adjust the electrodes so that the plug will have a spark gap of a length found to result in the best and most efrcient operation of the ignition system ofthe engine with which the plug is used. The spark gap may be gauged to .judge as to the necessity for bending the extremities of the shell electrodes toward the central electrode, as aforesaid, and to determine when said electrodes have been bent enough and when a proper length of spark gap has been secured, by such a Spark plug gap gauge as is disclosed in the patent to Hector Rabezzana, No. 1,993,896, March l2, 1935.

The preferred form of the gap adjusting device wherein our invention consists is illustrated in the drawing accompanying and forming a part of this specification and therein:

Figure 1 is a View showing our invention in side elevation, parts being broken away to better illustrate the operation thereof. y

Figure 2 is a view showing the same in plan. Both these views show a spark plugsupported by the device as it is supported preparatory to bending the ground electrodes inward.

Figure 3 is a view showing a section upon a horizontal plane indicated by the line 3-3, Figure 1, looking down.

Figure 4 is a view showing a section upon a vertical plane indicated by the line 4-4, Figure 2, looking toward the left.

Referring now to the drawing, the numeral 5 designates a base member having a pedestal portion 6 designed to be fastened to a bench, shelf or equivalent support, and which base has means at its left hand end for supporting a spark plug 'I the grounded or shell electrodes 8 of which are to be bent inward and toward the central electrode 9; so as to provide a spark gap of proper length between the extremities of the grounded shell electrodes and the insulated central 'electrode of the plug. The means for supporting the plug, the shell electrodes 'of which are to be adjusted, may b'e` of any form suitable for that purpose. As shown, the base 5 is bifurcated to provide two parallel arms I0, I0; and between these arms there is a supporting member I I, the side edgesof which rest upon and are adjustable along seats I2, I2 upon the inner sides of the arms I0', I0; the supporting member II having grooves I 3, I3 into which pins I4, I4 extend, see Figure 4, to thereby retain the supporting member in place as it is moved along the'arm's and seats. The numeral I5 designates a bolt extending through holes "adjacent the ends' of the arms I0, I0, and'having a nut I6 whereby said arms may be drawn together'to thereby grasp the 4sides of the support= ing member II and clamp it between the arms; and I'I'is 'an adjusting member which is rotatable upon the bolt I5' and against which the left hand end of the member II abuts, as shown. Suitable` collars' I8, I8 and washers I9, I9 ll the spaces' between the ends of the memberV Il and the inner sides of the arms I0, I0; and' by loosening the nut' I6 and manipulating 'the member I'Iy and the supporting member II; the latter may be placed variously along the arms; By 'tightening the nut I6 these parts will ybe locked together and will comprise a single rigid structure. f This adjusting operation is to adapt our device for operation upon sparkplugs having 'a particular definite diameter of threaded shell part which screws into the spark plug opening in 'an engine cylinder, and when properly adjusted as aforesaid for plugs having a particular diameter of thread will need to be re-adjusted only when the device is to be, used to bend the grounded electrodes of spark plugs having a different diamy eter of threaded shell. l

The supporting member I I thas a circular opening therein and rotatable in said opening and supported by said supporting member is an internally threaded spark plug adapter 2'0, which is threaded appropriately to receive the threaded shell of the particular spark plug to be operated upon.

In using our device an adapter having an internal thread of the proper diameter and pitch is screwed onto the threaded casing or shell of a spark plug and the adapter is placed in the circular opening in the supporting member I the adapter serving as a support for the plug as shown infFigure 1, and thereafter the grounded shell electrodes are bent inward toward the central electrode, separately and in succession, to thereby provide a spark gap of the proper length; the plug and the adapter being rotatable about the longitudinal axis of the plug vso as to bring each shell electrode 8 into position to be operated upon as will next appear.

The numeral 2| designates a lever which is pivotally supported from the base member 5 as by a pin 22 which extends through holes at the upper ends of pedestals 23, 23 extending upwardly from the base. This lever is located above the base and extends longitudinally thereof in the form of our invention illustrated; and the numeral 24 designates a tool point located at the left hand end thereof and adapted to engage a shell electrode 8 of the plug as shown in Figure 1, and force the extremity thereof toward the central electrode 9 when the lever is swung upon its pivotal support 22, to thereby secure a spark gap of the proper length between the electrodes. This bending operation will be performed upon each shell electrode as they are moved into positions to be engaged by the tool point, by rotating the adapter in the seat provided for it in the support as will be understood. The tool point 24 may be supported variously from the end of the lever 2| but it is preferably carried by a yoke 25 pivotally connected to the lever 2| by a pivot pin 26; so that the extremity of the tool point may seat itself properly, and without constraint as regards swinging movement upon f the pivot 26, as the tool point is forced against the grounded shell electrode to be bent.

The numeral 21 designates a nut having trunnions 28, 28 whereby it is supported from the right hand end of the lever 2|, see Figure 3, and 29 is a screw in threaded engagement with said nut and the lower end of which abuts against the base member 5 substantially as shown, said screw having a hand wheel 30 whereby it may be turned; to thereby force the tool point 24 against a grounded shell electrode 8 of the spark plug 1 toward the central electrode 9 thereof as will be understood.

Having thus described and explained our invention we claim and desire to secure by Letters Patent:

1. In a device of the class described, a base member bifurcated at one end to provide two parallel arms; a support arranged between and supported by, and adjustable along said arms; a rotatable adjusting member located between the ends of said arms, and which member acts to determine the positionof said support; an internally threaded spark plug adapter supported by said support and rotatable in a circular seat provided therein; a lever pivotally supported from and located above said base, and having a tool point adapted to engage a grounded shell electrode of a spark plug supported by said rotatable spark plug adapter; and means associated with the other ends of said lever and base for forcing said tool point against a shell electrode of a spark plug supported by said spark plug adapter.

2. In a device of the class described, a base member; a rotatable internally threaded spark plug adapter adapted to receive the threaded shell of a spark plug; means adjacent one end of said base for supporting said spark plug adapter therefrom; a lever pivotally supported from and located above said base; a tool point pivotally secured to one end of said lever and adapted to engage a grounded shell electrode of a spark plug supported by said rotatable spark plug adapter; and means associated with said lever and with said base for forcing said tool point against a shell electrode of spark plug supported by said internally threaded spark plug adapter.

3. In a device of the class described, a base member bifurcated at one end to provide two parallel arms; a support arranged between and supported by said arms and the sides of which contact with the inner sides of said arms, and which support has a circular seat; a bolt extending through holes adjacent the ends of said arms for drawing said arms toward one another to thereby clamp said support between said arms; an internally threaded spark plug adapter supported by said support and rotatable in the cir'- cular seat aforesaid; a lever pivotally supported from and located above said base, and having a tool point adapted to engage a grounded electrode of a spark plug supported by said rotatable spark plug adapter; and means associated with said lever and with said base for forcing said tool point against a shell electrode of a spark plug supported by said spark plug adapter.

4. In a device of the class described, a base member; a pivotally supported lever carried by and extending longitudinally of said base member; means carried by said base member for supporting a spark plug so that it may be rotated about its longitudinal axis; a tool point pivotally secured to one end of said lever and adapted to engage a grounded shell electrode of a spark plug supported by said base member; and means associated with said lever and with said base for forcing said tool point against a shell electrode of a spark plug supported as aforesaid.

5. In a device of the class described, a base member bifurcated at one end to provide two parallel arms; spark plug supporting means arranged between and adjustable along said arms; means for securing said spark plug supporting means in definite positions along said arms; a lever pivotally supported by and located above said base, and having a tool point adapted to engage a grounded shell electrode of a spark plug supported by said spark plug supporting means; and means associated with said lever and base for forcing said tool point against a shell electrode of a spark plug supported by said spark plug supporting means.

HECTOR RABEZZANA. ALEXANDER J BATTEY. 

